function convertCurrency(currencyDigits) { 
// Constants: 
    var MAXIMUM_NUMBER = 99999999999.99; 
    // Predefine the radix characters and currency symbols for output: 
    var CN_ZERO = "零"; 
    var CN_ONE = "壹"; 
    var CN_TWO = "贰"; 
    var CN_THREE = "叁"; 
    var CN_FOUR = "肆"; 
    var CN_FIVE = "伍"; 
    var CN_SIX = "陆"; 
    var CN_SEVEN = "柒"; 
    var CN_EIGHT = "捌"; 
    var CN_NINE = "玖"; 
    var CN_TEN = "拾"; 
    var CN_HUNDRED = "佰"; 
    var CN_THOUSAND = "仟"; 
    var CN_TEN_THOUSAND = "万"; 
    var CN_HUNDRED_MILLION = "亿"; 
    var CN_SYMBOL = "人民币"; 
    var CN_DOLLAR = "元"; 
    var CN_TEN_CENT = "角"; 
    var CN_CENT = "分"; 
    var CN_INTEGER = "整"; 
     
// Variables: 
    var integral;    // Represent integral part of digit number. 
    var decimal;    // Represent decimal part of digit number. 
    var outputCharacters;    // The output result. 
    var parts; 
    var digits, radices, bigRadices, decimals; 
    var zeroCount; 
    var i, p, d; 
    var quotient, modulus; 
     
// Validate input string: 
    currencyDigits = currencyDigits.toString(); 
    if (currencyDigits == "") { 
        alert("请输入小写金额！"); 
        return ""; 
    } 
    if (currencyDigits.match(/[^,.\d]/) != null) { 
        alert("小写金额含有无效字符！"); 
        return ""; 
    } 
    if ((currencyDigits).match(/^((\d{1,3}(,\d{3})*(.((\d{3},)*\d{1,3}))?)|(\d+(.\d+)?))$/) == null) { 
        alert("小写金额的格式不正确！"); 
        return ""; 
    } 
     
// Normalize the format of input digits: 
    currencyDigits = currencyDigits.replace(/,/g, "");    // Remove comma delimiters. 
    currencyDigits = currencyDigits.replace(/^0+/, "");    // Trim zeros at the beginning. 
    // Assert the number is not greater than the maximum number. 
    if (Number(currencyDigits) > MAXIMUM_NUMBER) { 
        alert("金额过大，应小于1000亿元！"); 
        return ""; 
    } 
     
// Process the coversion from currency digits to characters: 
    // Separate integral and decimal parts before processing coversion: 
    parts = currencyDigits.split("."); 
    if (parts.length > 1) { 
        integral = parts[0]; 
        decimal = parts[1]; 
        // Cut down redundant decimal digits that are after the second. 
        decimal = decimal.substr(0, 2); 
    } 
    else { 
        integral = parts[0]; 
        decimal = ""; 
    } 
    // Prepare the characters corresponding to the digits: 
    digits = new Array(CN_ZERO, CN_ONE, CN_TWO, CN_THREE, CN_FOUR, CN_FIVE, CN_SIX, CN_SEVEN, CN_EIGHT, CN_NINE); 
    radices = new Array("", CN_TEN, CN_HUNDRED, CN_THOUSAND); 
    bigRadices = new Array("", CN_TEN_THOUSAND, CN_HUNDRED_MILLION); 
    decimals = new Array(CN_TEN_CENT, CN_CENT); 
    // Start processing: 
    outputCharacters = ""; 
    // Process integral part if it is larger than 0: 
    if (Number(integral) > 0) { 
        zeroCount = 0; 
        for (i = 0; i < integral.length; i++) { 
            p = integral.length - i - 1; 
            d = integral.substr(i, 1); 
            quotient = p / 4; 
            modulus = p % 4; 
            if (d == "0") { 
                zeroCount++; 
            } 
            else { 
                if (zeroCount > 0) 
                { 
                    outputCharacters += digits[0]; 
                } 
                zeroCount = 0; 
                outputCharacters += digits[Number(d)] + radices[modulus]; 
            } 
            if (modulus == 0 && zeroCount < 4) { 
                outputCharacters += bigRadices[quotient]; 
                zeroCount = 0; 
            } 
        } 
        outputCharacters += CN_DOLLAR; 
    } 
    // Process decimal part if there is: 
    if (decimal != "") { 
        for (i = 0; i < decimal.length; i++) { 
            d = decimal.substr(i, 1); 
            if (d != "0") { 
                outputCharacters += digits[Number(d)] + decimals[i]; 
            } 
        } 
    } 
    // Confirm and return the final output string: 
    if (outputCharacters == "") { 
        outputCharacters = CN_ZERO + CN_DOLLAR; 
    } 
    if (decimal == "") { 
        outputCharacters += CN_INTEGER; 
    } 
    outputCharacters = outputCharacters; 
    return outputCharacters; 
} 